80275-06-5Relevant academic research and scientific papers
Cobalt-Catalyzed α-Arylation of Substituted α-Halogeno β-Lactams
Koch, Vanessa,Lorion, Mélanie M.,Barde, Etienne,Br?se, Stefan,Cossy, Janine
supporting information, p. 6241 - 6244 (2019/08/26)
The treatment of 3-bromo β-lactams by an aryl Grignard, in the presence of CoCl2 (2 mol %) and TMEDA (2 mol %) in THF, produces 3-aryl β-lactams in good yields and excellent diastereoselectivity.
Mechanistic Studies on the Michael Addition of Amines and Hydrazines to Nitrostyrenes: Nitroalkane Elimination via a Retro-aza-Henry-Type Process
Kallitsakis, Michael G.,Tancini, Peter D.,Dixit, Mudit,Mpourmpakis, Giannis,Lykakis, Ioannis N.
, p. 1176 - 1184 (2018/02/09)
In this article we report on the mechanistic studies of the Michael addition of amines and hydrazines to nitrostyrenes. Under the present conditions, the corresponding N-alkyl/aryl substituted benzyl imines and N-methyl/phenyl substituted benzyl hydrazones were observed via a retro-aza-Henry-type process. By combining organic synthesis and characterization experiments with computational chemistry calculations, we reveal that this reaction proceeds via a protic solvent-mediated mechanism. Experiments in deuterated methanol CD3OD reveal the synthesis and isolation of the corresponding deuterated intermediated Michael adduct, results that support the proposed slovent-mediated pathway. From the synthetic point of view, the reaction occurs under mild, noncatalytic conditions and can be used as a useful platform to yield the biologically important N-methyl pyrazoles in a one-pot manner, simple starting with the corresponding nitrostyrenes and the methylhydrazine.
Tf2O-TMDS combination for the direct reductive transformation of secondary amides to aldimines, aldehydes, and/or amines
Lang, Qi-Wei,Hu, Xiu-Ning,Huang, Pei-Qiang
, p. 1638 - 1644 (2016/12/07)
The direct partial reduction of highly stable secondary amides to more reactive aldimines and aldehydes is a challenging yet highly demanding transformation. In this context, only three methods have been reported. We report herein an improved version of the Charette’s method. Our protocol consists of activation of secondary amides with triflic anhydride/2-fluoropyridine, and partial reduction of the resulting intermediates with 1,1,3,3-tetramethyldisiloxane (TMDS), which delivered aldimines or aldehydes upon acidic hydrolysis. Aromatic amides were reduced to the corresponding aldimines in 85%–100% NMR yields, and yields (NMR) from aliphatic amides were 72%–86%. Acidic hydrolysis of the aldimine intermediates afforded, in one-pot, the corresponding aldehydes in 80%–96% yields. A simple protocol was established to isolate labile aldimines in pure form in 92%–96% yields. The improved method gave generally higher yields as compared to the known ones, and features the use of cheaper and more atom-economical TMDS as a chemoselective reducing agent. In addition, a convenient extraction protocol has been established to allow the isolation of amines, which constitutes a mild method for the N-deacylation of amides, another highly desirable transformation. The extended method retains the advantages of the original method of Charette in terms of mild conditions, good functional group tolerance, and excellent chemoselectivity.
Palladium-catalyzed aryl iodide carbonylation as a route to imidazoline synthesis: Design of a five-component coupling reaction
Bontemps, Sebastien,Quesnel, Jeffrey S.,Worrall, Kraig,Arndtsen, Bruce A.
supporting information; body text, p. 8948 - 8951 (2011/10/19)
Take five: A new method employing aryl halide carbonylation to directly access heterocycles has been described (see scheme). In a single palladium-catalyzed reaction the catalyst mediates two consecutive carbonylation steps, thereby converting five components (aryl iodide, two units imine, and two units CO) into an imidazoline ring.
Application of sequential Cu(I)/Pd(0)-catalysis to solution-phase parallel synthesis of combinatorial libraries of dihydroindeno[1,2-c]isoquinolines
Kumar, Sarvesh,Painter, Thomas O.,Pal, Benoy K.,Neuenswander, Benjamin,Malinakova, Helena C.
body text, p. 466 - 477 (2011/11/06)
Parallel solution-phase synthesis of combinatorial libraries of dihydroindenoisoquinolines employing a sequential Cu(I)/Pd(0)-catalyzed multicomponent coupling and annulation protocol was realized. The scope and limitations of the protocol with respect to the substitution pattern in the aryl ring of the indene core, as well as the N-substituent have been defined, revealing that the methodology is compatible with a wide-range of aliphatic linear, branched, and ester functionalized N-substituents. Unexpectedly, the formation of regioisomers featuring a 1,2,3-contiguous substitution pattern in the aromatic ring of the indene core was observed. Three distinct combinatorial libraries with a total of 111 of members were synthesized, and 80 highly substituted dihydroindenoisoquinolines structurally related to known medicinal agents including some consisting of mixtures of two regioisomers were made available for biological activity testing.
Reactions of N-(arylsulfonoxy)-N-alkylbenzylamines with MeONa-MeOH. Steric effect on the structure of the imine-forming transition state
Cho, Bong Rae,Pyun, Sang Yong
, p. 3920 - 3924 (2007/10/02)
Elimination reactions of N-(arylsulfonoxy)-N-alkylbenzylamines 1-5 with MeONa-MeOH have been studied kinetically. The elimination reactions are regiospecific, producing only corresponding benzylidenalkylamines. The rate equation for the reactions is kobs = k0 + k2[MeONa], indicating that the reactions proceed by competing solvolytic- and base-promoted pathways. The relative rates of elimination for the k2 and k0 pathways are 1, 0.67, 0.53, 0.35, and 0.27 for R = Me, Et, i-Pr, s-Bu, and t-Bu and 1, 4.1, 5.1, and 8.7 for R = Et, i-Pr, s-Bu, and t-Bu, respectively. For MeONa-promoted elimination from 1-5, Hammett ρ and kH/kD decrease but ρ1g and |β1g| increase with a bulkier alkyl substituent. However, the values for the solvolytic eliminations are nearly the same for all substrates and are similar to those for the base-promoted pathway, except for the ρ values, which have opposite signs. From these results, the changes in transition-state structure wrought by variation of N-alkyl substituents are assessed.
